/// \file
/// \ingroup tutorial_eve
/// Complex example showing ALICE ESD visualization in several views.
///   alice_esd_split.C - a simple event-display for ALICE ESD tracks and clusters
///                       version with several windows in the same workspace
///
///
///   Only standard ROOT is used to process the ALICE ESD files.
///
///   No ALICE code is needed, only four simple coordinate-transformation
///   functions declared in this macro.
///
///   A simple geometry of 10KB, extracted from the full TGeo-geometry, is
///   used to outline the central detectors of ALICE.
///
///   All files are access from the web by using the "CACHEREAD" option.
///
///
///   ### Automatic building of ALICE ESD class declarations and dictionaries.
///
///   ALICE ESD is a TTree containing tracks and other event-related
///   information with one entry per event. All these classes are part of
///   the AliROOT offline framework and are not available to standard
///   ROOT.
///
///   To be able to access the event data in a natural way, by using
///   data-members of classes and object containers, the header files and
///   class dictionaries are automatically generated from the
///   TStreamerInfo classes stored in the ESD file by using the
///   TFile::MakeProject() function. The header files and a shared library
///   is created in the aliesd/ directory and can be loaded dynamically
///   into the ROOT session.
///
///   See the run_alice_esd.C macro.
///
///
///   ### Creation of simple GUI for event navigation.
///
///   Most common use of the event-display is to browse through a
///   collection of events. Thus a simple GUI allowing this is created in
///   the function make_gui().
///
///   Eve uses the configurable ROOT-browser as its main window and so we
///   create an extra tab in the left working area of the browser and
///   provide backward/forward buttons.
///
///
///   ### Event-navigation functions.
///
///   As this is a simple macro, we store the information about the
///   current event in the global variable 'Int_t esd_event_id'. The
///   functions for event-navigation simply modify this variable and call
///   the load_event() function which does the following:
///   1. drop the old visualization objects;
///   2. retrieve given event from the ESD tree;
///   3. call alice_esd_read() function to create visualization objects
///      for the new event.
///
///
///   ### Reading of ALICE data and creation of visualization objects.
///
///   This is performed in alice_esd_read() function, with the following
///   steps:
///   1. create the track container object - TEveTrackList;
///   2. iterate over the ESD tracks, create TEveTrack objects and append
///      them to the container;
///   3. instruct the container to extrapolate the tracks and set their
///      visual attributes.
///
/// \image html eve_alice_esd_split.png
/// \macro_code
///
/// \author Bertrand Bellenot

#include "TEveProjectionManager.h"
#include "aliesd/AliESDEvent.h"
#include "aliesd/AliESDRun.h"
#include "aliesd/AliESDtrack.h"

R__EXTERN TEveProjectionManager *gRPhiMgr;
R__EXTERN TEveProjectionManager *gRhoZMgr;
TEveGeoShape *gGeoShape;

class AliESDEvent;
class AliESDfriend;
class AliESDtrack;
class AliExternalTrackParam;

void       make_gui();
void       load_event();
void       update_projections();

void       alice_esd_read();
TEveTrack* esd_make_track(TEveTrackPropagator* trkProp, Int_t index, AliESDtrack* at,
                          AliExternalTrackParam* tp=0);
Bool_t     trackIsOn(AliESDtrack* t, Int_t mask);
void       trackGetPos(AliExternalTrackParam* tp, Double_t r[3]);
void       trackGetMomentum(AliExternalTrackParam* tp, Double_t p[3]);
Double_t   trackGetP(AliExternalTrackParam* tp);


// Configuration and global variables.

const char* esd_file_name         = "http://root.cern.ch/files/alice_ESDs.root";
const char* esd_friends_file_name = "http://root.cern.ch/files/alice_ESDfriends.root";
const char* esd_geom_file_name    = "http://root.cern.ch/files/alice_ESDgeometry.root";

TFile *esd_file          = nullptr;
TFile *esd_friends_file  = nullptr;

TTree *esd_tree          = nullptr;

AliESDEvent  *esd        = nullptr;
AliESDfriend *esd_friend = nullptr;

Int_t esd_event_id       = 0; // Current event id.

TEveTrackList *track_list = nullptr;

TGTextEntry *gTextEntry   = nullptr;
TGHProgressBar *gProgress = nullptr;

/******************************************************************************/
// Initialization and steering functions
/******************************************************************************/

//______________________________________________________________________________
void run_alice_esd_split(Bool_t auto_size=kFALSE)
{
   // Main function, initializes the application.
   //
   // 1. Load the auto-generated library holding ESD classes and ESD dictionaries.
   // 2. Open ESD data-files.
   // 3. Load cartoon geometry.
   // 4. Spawn simple GUI.
   // 5. Load first event.

   TFile::SetCacheFileDir(".");

   printf("*** Opening ESD ***\n");
   esd_file = TFile::Open(esd_file_name, "CACHEREAD");
   if (!esd_file)
      return;

   printf("*** Opening ESD-friends ***\n");
   esd_friends_file = TFile::Open(esd_friends_file_name, "CACHEREAD");
   if (!esd_friends_file)
      return;

   esd_tree = (TTree*) esd_file->Get("esdTree");

   esd = (AliESDEvent*) esd_tree->GetUserInfo()->FindObject("AliESDEvent");

   // Set the branch addresses.
   {
      TIter next(esd->fESDObjects);
      TObject *el;
      while ((el=(TNamed*)next()))
      {
         TString bname(el->GetName());
         if(bname.CompareTo("AliESDfriend")==0)
         {
            // AliESDfriend needs some '.' magick.
            esd_tree->SetBranchAddress("ESDfriend.", esd->fESDObjects->GetObjectRef(el));
         }
         else
         {
            esd_tree->SetBranchAddress(bname, esd->fESDObjects->GetObjectRef(el));
         }
      }
   }

   TEveManager::Create();

   // Adapt the main frame to the screen size...
   if (auto_size)
   {
      Int_t qq;
      UInt_t ww, hh;
      gVirtualX->GetWindowSize(gVirtualX->GetDefaultRootWindow(), qq, qq, ww, hh);
      Float_t screen_ratio = (Float_t)ww/(Float_t)hh;
      if (screen_ratio > 1.5) {
         gEve->GetBrowser()->MoveResize(100, 50, ww - 300, hh - 100);
      } else {
         gEve->GetBrowser()->Move(50, 50);
      }
   }

   { // Simple geometry
      TFile* geom = TFile::Open(esd_geom_file_name, "CACHEREAD");
      if (!geom)
         return;
      TEveGeoShapeExtract* gse = (TEveGeoShapeExtract*) geom->Get("Gentle");
      gGeoShape = TEveGeoShape::ImportShapeExtract(gse, 0);
      geom->Close();
      delete geom;
      gEve->AddGlobalElement(gGeoShape);
   }

   make_gui();

   // import the geometry in the projection managers
   if (gRPhiMgr) {
      TEveProjectionAxes* a = new TEveProjectionAxes(gRPhiMgr);
      a->SetNdivisions(3);
      gEve->GetScenes()->FindChild("R-Phi Projection")->AddElement(a);
      gRPhiMgr->ImportElements(gGeoShape);
   }
   if (gRhoZMgr) {
      TEveProjectionAxes* a = new TEveProjectionAxes(gRhoZMgr);
      a->SetNdivisions(3);
      gEve->GetScenes()->FindChild("Rho-Z Projection")->AddElement(a);
      gRhoZMgr->ImportElements(gGeoShape);
   }

   load_event();

   update_projections();

   gEve->Redraw3D(kTRUE); // Reset camera after the first event has been shown.
}

//______________________________________________________________________________
void load_event()
{
   // Load event specified in global esd_event_id.
   // The contents of previous event are removed.

   printf("Loading event %d.\n", esd_event_id);
   gTextEntry->SetTextColor(0xff0000);
   gTextEntry->SetText(Form("Loading event %d...",esd_event_id));
   gSystem->ProcessEvents();

   if (track_list)
      track_list->DestroyElements();

   esd_tree->GetEntry(esd_event_id);

   alice_esd_read();

   gEve->Redraw3D(kFALSE, kTRUE);
   gTextEntry->SetTextColor((Pixel_t)0x000000);
   gTextEntry->SetText(Form("Event %d loaded",esd_event_id));
   gROOT->ProcessLine("SplitGLView::UpdateSummary()");
}

//______________________________________________________________________________
void update_projections()
{
   // cleanup then import geometry and event
   // in the projection managers

   TEveElement* top = gEve->GetCurrentEvent();
   if (gRPhiMgr && top) {
      gRPhiMgr->DestroyElements();
      gRPhiMgr->ImportElements(gGeoShape);
      gRPhiMgr->ImportElements(top);
   }
   if (gRhoZMgr && top) {
      gRhoZMgr->DestroyElements();
      gRhoZMgr->ImportElements(gGeoShape);
      gRhoZMgr->ImportElements(top);
   }
}

/******************************************************************************/
// GUI
/******************************************************************************/

//______________________________________________________________________________
//
// EvNavHandler class is needed to connect GUI signals.

class EvNavHandler
{
public:
   void Fwd()
   {
      if (esd_event_id < esd_tree->GetEntries() - 1) {
         ++esd_event_id;
         load_event();
         update_projections();
      } else {
         gTextEntry->SetTextColor(0xff0000);
         gTextEntry->SetText("Already at last event");
         printf("Already at last event.\n");
      }
   }
   void Bck()
   {
      if (esd_event_id > 0) {
         --esd_event_id;
         load_event();
         update_projections();
      } else {
         gTextEntry->SetTextColor(0xff0000);
         gTextEntry->SetText("Already at first event");
         printf("Already at first event.\n");
      }
   }
};

//______________________________________________________________________________
void make_gui()
{
   // Create minimal GUI for event navigation.

   gROOT->ProcessLine(".L SplitGLView.C+");

   TEveBrowser* browser = gEve->GetBrowser();

   browser->ShowCloseTab(kFALSE);
   browser->ExecPlugin("SplitGLView", 0, "new SplitGLView(gClient->GetRoot(), 600, 450, kTRUE)");
   browser->ShowCloseTab(kTRUE);

   browser->StartEmbedding(TRootBrowser::kLeft);

   TGMainFrame* frmMain = new TGMainFrame(gClient->GetRoot(), 1000, 600);
   frmMain->SetWindowName("XX GUI");
   frmMain->SetCleanup(kDeepCleanup);

   TGHorizontalFrame* hf = new TGHorizontalFrame(frmMain);
   {

      TString icondir( Form("%s/icons/", gSystem->Getenv("ROOTSYS")) );
      TGPictureButton* b = 0;
      EvNavHandler    *fh = new EvNavHandler;

      b = new TGPictureButton(hf, gClient->GetPicture(icondir + "GoBack.gif"));
      hf->AddFrame(b, new TGLayoutHints(kLHintsLeft | kLHintsCenterY, 10, 2, 10, 10));
      b->Connect("Clicked()", "EvNavHandler", fh, "Bck()");

      b = new TGPictureButton(hf, gClient->GetPicture(icondir + "GoForward.gif"));
      hf->AddFrame(b, new TGLayoutHints(kLHintsLeft | kLHintsCenterY, 2, 10, 10, 10));
      b->Connect("Clicked()", "EvNavHandler", fh, "Fwd()");

      gTextEntry = new TGTextEntry(hf);
      gTextEntry->SetEnabled(kFALSE);
      hf->AddFrame(gTextEntry, new TGLayoutHints(kLHintsLeft | kLHintsCenterY  |
                   kLHintsExpandX, 2, 10, 10, 10));
   }
   frmMain->AddFrame(hf, new TGLayoutHints(kLHintsTop | kLHintsExpandX,0,0,20,0));

   gProgress = new TGHProgressBar(frmMain, TGProgressBar::kFancy, 100);
   gProgress->ShowPosition(kTRUE, kFALSE, "%.0f tracks");
   gProgress->SetBarColor("green");
   frmMain->AddFrame(gProgress, new TGLayoutHints(kLHintsExpandX, 10, 10, 5, 5));

   frmMain->MapSubwindows();
   frmMain->Resize();
   frmMain->MapWindow();

   browser->StopEmbedding();
   browser->SetTabTitle("Event Control", 0);
}


/******************************************************************************/
// Code for reading AliESD and creating visualization objects
/******************************************************************************/

enum ESDTrackFlags {
   kITSin=0x0001,kITSout=0x0002,kITSrefit=0x0004,kITSpid=0x0008,
   kTPCin=0x0010,kTPCout=0x0020,kTPCrefit=0x0040,kTPCpid=0x0080,
   kTRDin=0x0100,kTRDout=0x0200,kTRDrefit=0x0400,kTRDpid=0x0800,
   kTOFin=0x1000,kTOFout=0x2000,kTOFrefit=0x4000,kTOFpid=0x8000,
   kHMPIDpid=0x20000,
   kEMCALmatch=0x40000,
   kTRDbackup=0x80000,
   kTRDStop=0x20000000,
   kESDpid=0x40000000,
   kTIME=0x80000000
};

//______________________________________________________________________________
void alice_esd_read()
{
   // Read tracks and associated clusters from current event.

   AliESDRun    *esdrun = (AliESDRun*)    esd->fESDObjects->FindObject("AliESDRun");
   TClonesArray *tracks = (TClonesArray*) esd->fESDObjects->FindObject("Tracks");

   // This needs further investigation. Clusters not shown.
   // AliESDfriend *frnd   = (AliESDfriend*) esd->fESDObjects->FindObject("AliESDfriend");
   // printf("Friend %p, n_tracks:%d\n", frnd, frnd->fTracks.GetEntries());

   if (track_list == 0) {
      track_list = new TEveTrackList("ESD Tracks");
      track_list->SetMainColor(6);
      //track_list->SetLineWidth(2);
      track_list->SetMarkerColor(kYellow);
      track_list->SetMarkerStyle(4);
      track_list->SetMarkerSize(0.5);

      gEve->AddElement(track_list);
   }

   TEveTrackPropagator* trkProp = track_list->GetPropagator();
   trkProp->SetMagField( 0.1 * esdrun->fMagneticField ); // kGaus to Tesla

   gProgress->Reset();
   gProgress->SetMax(tracks->GetEntriesFast());
   for (Int_t n=0; n<tracks->GetEntriesFast(); ++n)
   {
      AliESDtrack* at = (AliESDtrack*) tracks->At(n);

      // If ITS refit failed, take track parameters at inner TPC radius.
      AliExternalTrackParam* tp = at;
      if (! trackIsOn(at, kITSrefit)) {
         tp = at->fIp;
      }

      TEveTrack* track = esd_make_track(trkProp, n, at, tp);
      track->SetAttLineAttMarker(track_list);
      track_list->AddElement(track);

      // This needs further investigation. Clusters not shown.
      // if (frnd)
      // {
      //     AliESDfriendTrack* ft = (AliESDfriendTrack*) frnd->fTracks->At(n);
      //     printf("%d friend = %p\n", ft);
      // }
      gProgress->Increment(1);
   }

   track_list->MakeTracks();
}

//______________________________________________________________________________
TEveTrack* esd_make_track(TEveTrackPropagator*   trkProp,
                          Int_t                  index,
                          AliESDtrack*           at,
                          AliExternalTrackParam* tp)
{
   // Helper function creating TEveTrack from AliESDtrack.
   //
   // Optionally specific track-parameters (e.g. at TPC entry point)
   // can be specified via the tp argument.

   Double_t      pbuf[3], vbuf[3];
   TEveRecTrack  rt;

   if (tp == 0) tp = at;

   rt.fLabel  = at->fLabel;
   rt.fIndex  = index;
   rt.fStatus = (Int_t) at->fFlags;
   rt.fSign   = (tp->fP[4] > 0) ? 1 : -1;

   trackGetPos(tp, vbuf);      rt.fV.Set(vbuf);
   trackGetMomentum(tp, pbuf); rt.fP.Set(pbuf);

   Double_t ep = trackGetP(at);
   Double_t mc = 0.138; // at->GetMass(); - Complicated function, requiring PID.

   rt.fBeta = ep/TMath::Sqrt(ep*ep + mc*mc);

   TEveTrack* track = new TEveTrack(&rt, trkProp);
   track->SetName(Form("TEveTrack %d", rt.fIndex));
   track->SetStdTitle();

   return track;
}

//______________________________________________________________________________
Bool_t trackIsOn(AliESDtrack* t, Int_t mask)
{
   // Check is track-flag specified by mask are set.

   return (t->fFlags & mask) > 0;
}

//______________________________________________________________________________
void trackGetPos(AliExternalTrackParam* tp, Double_t r[3])
{
   // Get global position of starting point of tp.

  r[0] = tp->fX; r[1] = tp->fP[0]; r[2] = tp->fP[1];

  Double_t cs=TMath::Cos(tp->fAlpha), sn=TMath::Sin(tp->fAlpha), x=r[0];
  r[0] = x*cs - r[1]*sn; r[1] = x*sn + r[1]*cs;
}

//______________________________________________________________________________
void trackGetMomentum(AliExternalTrackParam* tp, Double_t p[3])
{
   // Return global momentum vector of starting point of tp.

   p[0] = tp->fP[4]; p[1] = tp->fP[2]; p[2] = tp->fP[3];

   Double_t pt=1./TMath::Abs(p[0]);
   Double_t cs=TMath::Cos(tp->fAlpha), sn=TMath::Sin(tp->fAlpha);
   Double_t r=TMath::Sqrt(1 - p[1]*p[1]);
   p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2];
}

//______________________________________________________________________________
Double_t trackGetP(AliExternalTrackParam* tp)
{
   // Return magnitude of momentum of tp.

   return TMath::Sqrt(1.+ tp->fP[3]*tp->fP[3])/TMath::Abs(tp->fP[4]);
}
